This is a competing continuation application for a K05 Senior Scientist Award. The major goals are to continue and extend research on: (1) risk and protective factors involved in onset, stability and change in adolescent drug use; (2) testing models of pathways to drug use; and (3) consequences of drug use on young adult functioning. The proposed research will expand on and extend prior research by: (1) inclusion of samples of inner city youngsters and children of IV drug abusers; (2) study of intra- and intergenerational transmission of drug-prone characteristics; and (3) examination of factors related to AIDS transmission behavior and to coping with AIDS. In order to achieve these goals, an integrated program of research is underway involving five large-scale projects: (I) A longitudinal study of children and their mothers seen at five points in time beginning at ages 1-10; (II) A multigenerational study of two- year-old offspring of the original study child in Project I; (III) A study of inner city African-American and Puerto Rican adolescents; (IV) A study of adolescents and their mothers living in Columbia, South America; and (V) a study of HIV plus and HIV minus intravenous drug using fathers and their children. The major significance of this program of integrated research is that it addresses many critical issues in the drug field, e.g., what are the risks for drug use throughout the developmental span of childhood to young adulthood; what can protect against these risks; how do risk and protective factors operate in populations most likely to become involved in drug or other problem behaviors, including those implicated in the spread of AIDS; how can one break the transmission of risk from one generation to the next; and how can the consequences of drug use be averted or lessened. The K05 will enable me to devote my full time and energy to research goals such as substantive and methodological development, collaboration with investigators in other longitudinal studies, mentoring activities including guidance of high school and graduate students, medical students, and junior faculty.